Area Forecast Discussion
Issued by NWS Central Illinois

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000
FXUS63 KILX 130742
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
242 AM CDT Sun Aug 13 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 242 AM CDT Sun Aug 13 2017

Another quiet and pleasant day on tap, as high pressure slowly
drifts east across the Midwest. Some high clouds have been
spreading eastward into our area from a decaying convective
complex over Nebraska, but the thicker clouds are projected to
track across northern Illinois later this morning. High
temperatures will be fairly similar to yesterday, mainly a degree
or two either side of 80, with dew points in the comfortable 50s.

&&

.LONG TERM...(Monday through Saturday)
ISSUED AT 242 AM CDT Sun Aug 13 2017

Gradual air mass modification will take place this week as the
upper level winds start to orient themselves more out of the
southwest, and the upper trough over the Great Lakes tends to
retreat a bit northward. Main increase in humidity levels will
begin on Tuesday as the surface flow finally starts to come off
the Gulf, and conditions on Wednesday and Thursday will feel more
like typical summer weather. Late in the week, a more broad long
wave trough will move into the Mississippi Valley, with dew points
easing back down into the 60s.

Periodic shortwaves continue to be the main concern during this
part of the forecast. The Monday wave looks a little more robust
but more focused to our northwest, though some isolated storms
may make it down into our far northern CWA during the afternoon
and night. A few storms are possible again Tuesday over most of
the CWA, mainly more of an air mass type storm as there is not
much lift to get things going. Wednesday-Thursday remains the main
show with showers moving into the western CWA before sunrise
Wednesday. Timing and extent still a challenge, as the GFS and
Canadian models are on the slower side due to their amplification
of a east-shifting ridge over the area mid week. Highest PoP`s
will be Wednesday night as the ridge breaks down. However, the
ECMWF has less of a clean-cut frontal passage and lingers some
rain all the way into the first part of the weekend, when the
earlier mentioned long wave trough arrives. No real clear period
to go with significantly dry weather, although afternoon diurnal
convection is more favored late in the week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1230 AM CDT Sun Aug 13 2017

Only real concern for this TAF set is the potential for some fog
around dawn. Forecast soundings suggest if any occurs, it will be
very shallow. This was observed Saturday morning in similar
conditions. Have included a TEMPO group at all sites for the
10-12Z period for some patchy, shallow fog. Otherwise, diurnal
cumulus field is expected to start forming late morning once
again, mainly from KPIA-KCMI, starting around 3500 feet and edging
upward. The clouds should mostly fade before early evening.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Geelhart



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